from dataclasses import dataclass
from enum import Enum

from django.conf import settings
from django.db import transaction
from django.db.models import Count
from django.utils.translation import gettext as _
from django.utils.translation import override as override_language

from zerver.actions.create_realm import setup_realm_internal_bots
from zerver.actions.message_send import (
    do_send_messages,
    internal_prep_private_message,
    internal_prep_stream_message_by_name,
    internal_send_private_message,
)
from zerver.actions.reactions import do_add_reaction
from zerver.lib.emoji import get_emoji_data
from zerver.lib.markdown.fenced_code import get_unused_fence
from zerver.lib.message import SendMessageRequest, remove_single_newlines
from zerver.models import Message, OnboardingUserMessage, Realm, UserProfile
from zerver.models.groups import SystemGroups
from zerver.models.recipients import Recipient
from zerver.models.users import get_system_bot


@dataclass
class InitialDirectMessageIDs:
    welcome_bot_intro_message_id: int
    welcome_bot_custom_message_id: int | None


def missing_any_realm_internal_bots() -> bool:
    bot_emails = [
        bot["email_template"] % (settings.INTERNAL_BOT_DOMAIN,)
        for bot in settings.REALM_INTERNAL_BOTS
    ]
    realm_count = Realm.objects.count()
    return UserProfile.objects.filter(email__in=bot_emails).values("email").alias(
        count=Count("id")
    ).filter(count=realm_count).count() != len(bot_emails)


def create_if_missing_realm_internal_bots() -> None:
    """This checks if there is any realm internal bot missing.

    If that is the case, it creates the missing realm internal bots.
    """
    if missing_any_realm_internal_bots():
        for realm in Realm.objects.all().iterator():
            setup_realm_internal_bots(realm)


def get_custom_welcome_message_string(realm: Realm, welcome_message_custom_text: str) -> str:
    # TODO: This could use silent_mention_syntax_for_user_group, but
    # it's not worth doing a database query to get the NamedUserGroup,
    # so some refactoring is required to do that.
    mention_syntax = f"@_*{SystemGroups.ADMINISTRATORS}*"
    fence = get_unused_fence(welcome_message_custom_text)
    welcome_bot_custom_message_intro_string = _("A note from {admin_group_syntax}:").format(
        admin_group_syntax=mention_syntax
    )

    welcome_bot_custom_message_string = f"""
{welcome_bot_custom_message_intro_string}
{fence}quote
{welcome_message_custom_text}
{fence}
"""

    return welcome_bot_custom_message_string


def send_initial_direct_messages_to_user(
    user: UserProfile,
    *,
    welcome_message_custom_text: str = "",
) -> InitialDirectMessageIDs:
    # We adjust the initial Welcome Bot direct message for education organizations.
    education_organization = user.realm.org_type in (
        Realm.ORG_TYPES["education_nonprofit"]["id"],
        Realm.ORG_TYPES["education"]["id"],
    )
    welcome_bot_messages = []

    # We need to override the language in this code path, because it's
    # called from account registration, which is a pre-account API
    # request and thus may not have the user's language context yet.
    with override_language(user.default_language):
        if education_organization:
            getting_started_string = _("""
To learn more, check out our [using Zulip for a class guide]({getting_started_url})!
""").format(getting_started_url="/help/using-zulip-for-a-class")
        else:
            getting_started_string = _("""
To learn more, check out our [getting started guide]({getting_started_url})!
""").format(getting_started_url="/help/getting-started-with-zulip")

        organization_setup_string = ""
        # Add extra content on setting up a new organization for administrators.
        if user.is_realm_admin:
            if education_organization:
                organization_setup_string = _("""
We also have a guide for [setting up Zulip for a class]({organization_setup_url}).
""").format(organization_setup_url="/help/setting-up-zulip-for-a-class")
            else:
                organization_setup_string = _("""
We also have a guide for [moving your organization to Zulip]({organization_setup_url}).
""").format(organization_setup_url="/help/moving-to-zulip")

        demo_organization_warning_string = ""
        # Add extra content about automatic deletion for demo organization owners.
        if user.is_realm_owner and user.realm.demo_organization_scheduled_deletion_date is not None:
            demo_organization_warning_string = _("""
Note that this is a [demo organization]({demo_organization_help_url}) and
will be **automatically deleted** in 30 days, unless it's [converted into
a permanent organization]({convert_demo_organization_help_url}).
""").format(
                demo_organization_help_url="/help/demo-organizations",
                convert_demo_organization_help_url="/help/demo-organizations#convert-a-demo-organization-to-a-permanent-organization",
            )

        inform_about_tracked_onboarding_messages_text = ""
        if OnboardingUserMessage.objects.filter(realm_id=user.realm_id).exists():
            inform_about_tracked_onboarding_messages_text = _("""
I've kicked off some conversations to help you get started. You can find
them in your [Inbox](/#inbox).
""")

        navigation_tour_video_string = _("""
You can always come back to the [Welcome to Zulip video]({navigation_tour_video_url}) for a quick app overview.
""").format(navigation_tour_video_url=settings.NAVIGATION_TOUR_VIDEO_URL)

        welcome_bot_custom_message_string = ""
        # Add welcome bot custom message.
        if welcome_message_custom_text:
            welcome_bot_custom_message_string = get_custom_welcome_message_string(
                user.realm, welcome_message_custom_text
            )

        content = _("""
Hello, and welcome to Zulip!👋 {inform_about_tracked_onboarding_messages_text}

{getting_started_text} {organization_setup_text}

{navigation_tour_video_text}

{demo_organization_text}

""").format(
            inform_about_tracked_onboarding_messages_text=inform_about_tracked_onboarding_messages_text,
            getting_started_text=getting_started_string,
            organization_setup_text=organization_setup_string,
            navigation_tour_video_text=navigation_tour_video_string,
            demo_organization_text=demo_organization_warning_string,
        )

    welcome_bot_messages.append(
        internal_prep_private_message(
            get_system_bot(settings.WELCOME_BOT, user.realm_id),
            user,
            remove_single_newlines(content),
            # Note: Welcome bot doesn't trigger email/push notifications,
            # as this is intended to be seen contextually in the application.
            disable_external_notifications=True,
        )
    )

    if welcome_bot_custom_message_string:
        welcome_bot_messages.append(
            internal_prep_private_message(
                get_system_bot(settings.WELCOME_BOT, user.realm_id),
                user,
                welcome_bot_custom_message_string,
                disable_external_notifications=True,
            )
        )

    sent_messages = do_send_messages(welcome_bot_messages)

    welcome_bot_custom_message_id = None
    welcome_bot_intro_message_id = sent_messages[0].message_id
    if welcome_bot_custom_message_string:
        welcome_bot_custom_message_id = sent_messages[1].message_id

    return InitialDirectMessageIDs(
        welcome_bot_intro_message_id=welcome_bot_intro_message_id,
        welcome_bot_custom_message_id=welcome_bot_custom_message_id,
    )


def bot_commands(no_help_command: bool = False) -> str:
    commands = [
        "apps",
        "profile",
        "theme",
        "channels",
        "topics",
        "message formatting",
        "keyboard shortcuts",
    ]
    if not no_help_command:
        commands.append("help")
    return ", ".join("`" + command + "`" for command in commands) + "."


def select_welcome_bot_response(human_response_lower: str) -> str:
    # Given the raw (pre-markdown-rendering) content for a private
    # message from the user to Welcome Bot, select the appropriate reply.
    if human_response_lower in ["app", "apps"]:
        return _("""
You can [download](/apps/) the [mobile and desktop apps](/apps/).
Zulip also works great in a browser.
""")
    elif human_response_lower == "profile":
        return _("""
Go to [Profile settings](#settings/profile) to add a [profile picture](/help/change-your-profile-picture)
and edit your [profile information](/help/edit-your-profile).
""")
    elif human_response_lower == "theme":
        return _("""
You can switch between [light and dark theme](/help/dark-theme), [pick your
favorite emoji set](/help/emoji-and-emoticons#change-your-emoji-set), [change
your language](/help/change-your-language), and otherwise customize your Zulip
experience in your [Preferences](#settings/preferences).
""")
    elif human_response_lower in ["stream", "streams", "channel", "channels"]:
        return _("""
Channels organize conversations based on who needs to see them. For example,
it's common to have a channel for each team in an organization.

[Browse and subscribe to channels]({settings_link}).
""").format(help_link="/help/introduction-to-channels", settings_link="#channels/all")
    elif human_response_lower in ["topic", "topics"]:
        return _("""
[Topics](/help/introduction-to-topics) summarize what each conversation in Zulip
is about. You can read Zulip one topic at a time, seeing each message in
context, no matter how many other conversations are going on.

When you start a conversation, label it with a new topic. For a good topic name,
think about finishing the sentence: “Hey, can we chat about…?”

Check out [Recent conversations](#recent) for a list of topics that are being
discussed.
""")
    elif human_response_lower in ["keyboard", "shortcuts", "keyboard shortcuts"]:
        return _("""
Zulip's [keyboard shortcuts](#keyboard-shortcuts) let you navigate the app
quickly and efficiently.

Press `?` any time to see a [cheat sheet](#keyboard-shortcuts).
""")
    elif human_response_lower in ["formatting", "message formatting"]:
        return _("""
You can **format** *your* `message` using the handy formatting buttons, or by
typing your formatting with Markdown.

Check out the [cheat sheet](#message-formatting) to learn about spoilers, global
times, and more.
""")
    elif human_response_lower in ["help", "?"]:
        return _("""
Here are a few messages I understand: {bot_commands}

Check out our [Getting started guide](/help/getting-started-with-zulip),
or browse the [help center](/help/) to learn more!
""").format(bot_commands=bot_commands(no_help_command=True))
    else:
        return _("""
You can chat with me as much as you like! To
get help, try one of the following messages: {bot_commands}
""").format(bot_commands=bot_commands())


def send_welcome_bot_response(send_request: SendMessageRequest) -> None:
    """Given the send_request object for a direct message from the user
    to welcome-bot, trigger the welcome-bot reply."""
    welcome_bot = get_system_bot(settings.WELCOME_BOT, send_request.realm.id)
    human_response_lower = send_request.message.content.lower()
    if send_request.message.recipient.type == Recipient.PERSONAL:
        conversation_recipient_id = send_request.message.sender.recipient_id
        assert conversation_recipient_id is not None
    else:
        assert send_request.message.recipient.type == Recipient.DIRECT_MESSAGE_GROUP
        conversation_recipient_id = send_request.message.recipient.id
    content = select_welcome_bot_response(human_response_lower)
    realm_id = send_request.realm.id
    commands = bot_commands()
    if (
        commands in content
        and Message.objects.filter(
            realm_id=realm_id,
            sender_id=welcome_bot.id,
            recipient_id=conversation_recipient_id,
            content__icontains=commands,
        ).exists()
        # Uses index 'zerver_message_realm_sender_recipient'
    ):
        # If the bot has already sent bot commands to this user and
        # if the bot does not understand the current message sent by this user then
        # do not send any message
        return

    internal_send_private_message(
        welcome_bot,
        send_request.message.sender,
        remove_single_newlines(content),
        # Note: Welcome bot doesn't trigger email/push notifications,
        # as this is intended to be seen contextually in the application.
        disable_external_notifications=True,
    )


class OnboardingMessageTypeEnum(Enum):
    moving_messages = 1
    welcome_to_zulip = 2
    start_conversation = 3
    experiments = 4
    greetings = 5


@transaction.atomic(savepoint=False)
def send_initial_realm_messages(
    realm: Realm,
    override_channel_name_map: dict[OnboardingMessageTypeEnum, str | None] | None = None,
) -> None:
    """
    override_channel_name_map allows the caller to customize to which channels to send
    specific categories of the initial messages. In this override dict, every category
    from OnboardingMessageTypeEnum must be specified.

    The caller can disable the sending of a specific category by mapping it to None
    in override_channel_name_map.
    """

    if override_channel_name_map is not None:
        channel_name_map = override_channel_name_map
    else:
        channel_name_map = {
            OnboardingMessageTypeEnum.moving_messages: str(Realm.ZULIP_DISCUSSION_CHANNEL_NAME),
            OnboardingMessageTypeEnum.welcome_to_zulip: str(Realm.ZULIP_DISCUSSION_CHANNEL_NAME),
            OnboardingMessageTypeEnum.start_conversation: str(Realm.ZULIP_SANDBOX_CHANNEL_NAME),
            OnboardingMessageTypeEnum.experiments: str(Realm.ZULIP_SANDBOX_CHANNEL_NAME),
            OnboardingMessageTypeEnum.greetings: str(Realm.DEFAULT_NOTIFICATION_STREAM_NAME),
        }
    assert set(channel_name_map.keys()) == set(OnboardingMessageTypeEnum)

    # Sends the initial messages for a new organization.
    #
    # Technical note: Each stream created in the realm creation
    # process should have at least one message declared in this
    # function, to enforce the pseudo-invariant that every stream has
    # at least one message.
    welcome_bot = get_system_bot(settings.WELCOME_BOT, realm.id)

    # Content is declared here to apply translation properly.
    #
    # remove_single_newlines needs to be called on any multiline
    # strings for them to render properly.
    content1_of_moving_messages_topic_name = (
        _("""
If anything is out of place, it’s easy to [move messages]({move_content_another_topic_help_url}),
[rename]({rename_topic_help_url}) and [split]({move_content_another_topic_help_url}) topics,
or even move a topic [to a different channel]({move_content_another_channel_help_url}).
""")
    ).format(
        move_content_another_topic_help_url="/help/move-content-to-another-topic",
        rename_topic_help_url="/help/rename-a-topic",
        move_content_another_channel_help_url="/help/move-content-to-another-channel",
    )

    content2_of_moving_messages_topic_name = _("""
:point_right: Try moving this message to another topic and back.
""")

    content1_of_welcome_to_zulip_topic_name = _("""
Zulip is organized to help you communicate more efficiently. Conversations are
labeled with topics, which summarize what the conversation is about.

For example, this message is in the “{topic_name}” topic in the
#**{zulip_discussion_channel_name}** channel, as you can see in the left sidebar
and above.
""").format(
        zulip_discussion_channel_name=channel_name_map[OnboardingMessageTypeEnum.welcome_to_zulip],
        topic_name=_("welcome to Zulip!"),
    )

    content2_of_welcome_to_zulip_topic_name = _("""
You can read Zulip one conversation at a time, seeing each message in context,
no matter how many other conversations are going on.
""")

    content3_of_welcome_to_zulip_topic_name = _("""
:point_right: When you're ready, check out your [Inbox](/#inbox) for other
conversations with unread messages.
""")

    content1_of_start_conversation_topic_name = _("""
To kick off a new conversation, pick a channel in the left sidebar, and click
the `+` button next to its name.
""")

    content2_of_start_conversation_topic_name = _("""
Label your conversation with a topic. Think about finishing the sentence: “Hey,
can we chat about…?”
""")

    content3_of_start_conversation_topic_name = _("""
:point_right: Try starting a new conversation in this channel.
""")

    content1_of_experiments_topic_name = (
        _("""
:point_right:  Use this topic to try out [Zulip's messaging features]({format_message_help_url}).
""")
    ).format(format_message_help_url="/help/format-your-message-using-markdown")

    content2_of_experiments_topic_name = (
        _("""
```spoiler Want to see some examples?

````python

print("code blocks")

````

- bulleted
- lists

Link to a conversation: #**{zulip_discussion_channel_name}>{topic_name}**

```
""")
    ).format(
        zulip_discussion_channel_name=channel_name_map[OnboardingMessageTypeEnum.welcome_to_zulip],
        topic_name=_("welcome to Zulip!"),
    )

    content1_of_greetings_topic_name = _("""
This **greetings** topic is a great place to say “hi” :wave: to your teammates.
""")

    content2_of_greetings_topic_name = _("""
:point_right: Click on this message to start a new message in the same conversation.
""")

    welcome_messages: list[dict[str, str]] = []

    # Messages added to the "welcome messages" list last will be most
    # visible to users, since welcome messages will likely be browsed
    # via the right sidebar or recent conversations view, both of
    # which are sorted newest-first.
    #
    # Initial messages are configured below.

    # Advertising moving messages.
    if (
        moving_messages_channel_name := channel_name_map[OnboardingMessageTypeEnum.moving_messages]
    ) is not None:
        welcome_messages += [
            {
                "channel_name": moving_messages_channel_name,
                "topic_name": _("moving messages"),
                "content": content,
            }
            for content in [
                content1_of_moving_messages_topic_name,
                content2_of_moving_messages_topic_name,
            ]
        ]

    # Suggestion to test messaging features.
    # Dependency on knowing how to send messages.
    if (
        experiments_channel_name := channel_name_map[OnboardingMessageTypeEnum.experiments]
    ) is not None:
        welcome_messages += [
            {
                "channel_name": experiments_channel_name,
                "topic_name": _("experiments"),
                "content": content,
            }
            for content in [content1_of_experiments_topic_name, content2_of_experiments_topic_name]
        ]

    if (
        start_conversation_channel_name := channel_name_map[
            OnboardingMessageTypeEnum.start_conversation
        ]
    ) is not None:
        # Suggestion to start your first new conversation.
        welcome_messages += [
            {
                "channel_name": start_conversation_channel_name,
                "topic_name": _("start a conversation"),
                "content": content,
            }
            for content in [
                content1_of_start_conversation_topic_name,
                content2_of_start_conversation_topic_name,
                content3_of_start_conversation_topic_name,
            ]
        ]

    # Suggestion to send first message as a hi to your team.
    if (
        greetings_channel_name := channel_name_map[OnboardingMessageTypeEnum.greetings]
    ) is not None:
        welcome_messages += [
            {
                "channel_name": greetings_channel_name,
                "topic_name": _("greetings"),
                "content": content,
            }
            for content in [content1_of_greetings_topic_name, content2_of_greetings_topic_name]
        ]

    if (
        welcome_to_zulip_channel_name := channel_name_map[
            OnboardingMessageTypeEnum.welcome_to_zulip
        ]
    ) is not None:
        # Main welcome message, this should be last.
        welcome_messages += [
            {
                "channel_name": welcome_to_zulip_channel_name,
                "topic_name": _("welcome to Zulip!"),
                "content": content,
            }
            for content in [
                content1_of_welcome_to_zulip_topic_name,
                content2_of_welcome_to_zulip_topic_name,
                content3_of_welcome_to_zulip_topic_name,
            ]
        ]

    # End of message declarations; now we actually send them.

    messages = [
        internal_prep_stream_message_by_name(
            realm,
            welcome_bot,
            message["channel_name"],
            message["topic_name"],
            remove_single_newlines(message["content"]),
        )
        for message in welcome_messages
    ]
    message_ids = [
        sent_message_result.message_id for sent_message_result in do_send_messages(messages)
    ]

    seen_topics = set()
    onboarding_topics_first_message_ids = set()
    for index, message in enumerate(welcome_messages):
        topic_name = message["topic_name"]
        if topic_name not in seen_topics:
            onboarding_topics_first_message_ids.add(message_ids[index])
            seen_topics.add(topic_name)

    onboarding_user_messages = []
    for message_id in message_ids:
        flags = OnboardingUserMessage.flags.historical
        if message_id in onboarding_topics_first_message_ids:
            flags |= OnboardingUserMessage.flags.starred
        onboarding_user_messages.append(
            OnboardingUserMessage(realm=realm, message_id=message_id, flags=flags)
        )

    OnboardingUserMessage.objects.bulk_create(onboarding_user_messages)

    # We find the one of our just-sent greetings messages, and react to it.
    # This is a bit hacky, but works and is kinda a 1-off thing.
    greetings_message = (
        Message.objects.select_for_update()
        .filter(
            id__in=message_ids, content=remove_single_newlines(content1_of_greetings_topic_name)
        )
        .first()
    )
    assert greetings_message is not None
    emoji_data = get_emoji_data(realm.id, "wave")
    do_add_reaction(
        welcome_bot, greetings_message, "wave", emoji_data.emoji_code, emoji_data.reaction_type
    )
